Process of making phonograph-records.



T. A. EDISON.

PROCESS 0F MAKING YHONOGRAPH RECORDS.

APPLICATION PILE-I1 OGT.14. 190B` Lm. 132118111811 Nov. 11, 1913.

fffff: Q ///Z i' 11mm W 1 im UNITED STATES PATENT oEEroE.

'THOMAS E. EDISON, or LLEWEELYN PARK, o EaNGE, NEW JERSEY, as sTGNoR To NEW yJERSEY PATENT coMPANY, or WEST QRANGE, NEW JERSEY, A onroEATIoN or Application filled October Ill, 1908. Serial No. 457,593. l

yepts used for this irpose, as foi` example, 'chas commonly made a' liquid solution :from

acetate amyl, w use of for providing NEW JERSEY.

, PROCESS '0F MAKING BHONOGRAPH-BECDBDS.

11,978,265 .specification of Letters Patent.

To .all @We t may .Gower-cf Be it known ,that 4I, TilroirAs ALvA EDISON, e .citizen .ofthe Uni-ted States., and .a resident of lLlewellyn Park, ,Qrange, in the county Xof and Stategof New nJersey, have nvented certain ,new and useful Improvements in Prese-sees 0f Making Phonosraph- Records, of .which the following is adescriptionf v l t The yvaX-likecompositions now lin common use .far making phonograph records, such, for Aexam, le, as ,that described in Patent No. 782,3?, granted 1to Jonas Ayls- Wontli, have qualities `which make Ithem specially ,adapted rfor this purpose. Such materials .een he readily molded, sive an iw- Qurete copy ef the .Surface f the mold 0r. matrix, and lafter being molded ,can be reamed out ,t med oil and otherwise Worked with great facilit Phonog'rap'h records -can be made from these materials at low lcost, simple ymachinery and by' very cheap labor. It is a fact, however, that records made from these wax-like compositions and made as' is now the Iconunon practice, with substantially one hundred irecord grooves to the linch, aft-er being subjected -to a Ilarge number ofl reproductions on the phonograph, show signs of Wear and the character of the reproduction obtained therefrom is not so goed as at irSt. Obvi-I ously, Such records would be moreV rapidly worn a narrower record groove and a reproducing,r stylusof correspondingly decreased size are made use of. As it is desirable to increase the amount of record on the surface, it is necessary that such surface should be hardened. It is desirable, therefore, that a record be made which will have a harder and tougher wearing surface and .which will at the same time retain the good moldable and workable qualities of the records made from thewax-like compositions now used.

rl`he object of my invention is to produce a record of the sort just described, from wax or Wax-like composition, or other easily molded material, and having' a hardened wearing surface.

ln the practice of my invention l preferably take a duplicate or original phonograph record, which has been made in any of the usual Ways from the usual wax-like composition, and immerse it in a solution of nitrated cotton in any of the ordinary solwhicli iilms are made for p otographic use. I may, if desired, add a small'percentage'of camphor to' the nitrated cotton,".thus making a Celluloid =collodion solution','but ,this 'may b e dispensed with. V E

place the record ,upon adipping mandrel having' adjustable" extension' lend'si'at cach end of ,the record. It is' then immersed in the solution 'while'heldvertjcallyg' it is `,oa gentle then withdrawn .and ,subjected breeze from a fanto 'slightly aiect or harden 4:the surface; 't 'is` ,thenl lm'mersed a second ,time and lsubje'cte'd tothe zair. 'If the solution is rather thick, two'fsuch dips will giye a"sulicient-thickness o'film over the record when lthe latter is ied. Sometimes it is best ,to make Ithe solutionthinn'er when threeor more dips will ibe necessary. After the dips, theina'ndrel is transferred' to 'a machine'which 'rotates jit ina horizontal position unt-il nearlyfree Ifro-In solvent, when it may be 'taken' ofi the mandrel and set aside until the whole of the solvent has-evaporated, leaving'avery hard 'tough film on the surface ofthe recor It is a remarkable lfact', and entirelylunexpected, that although the average depth off'the'indentat'onspn a record is only 4half of one thousandth of an inch and the greatest depth one -thousandth of an inch, yet, if the thickness of the'lm of `the''nitro-cella'- lose"yvhen dry is threethousandths of an inch, a' perfect replica ol the record Aunderlulose above, even to t-he finest detail, and what is -more strange is that the depth of the wave is so little affected that theloss in the volume of sound is scarcely noticeable'.

Velydeep records can be made and the reproducing balls can be pressed lwith sufficient force against the cellulose as to cause it to :follow the record Without injury to it, which would be impossible if the ball was forced against the record surface below. Thus, the volume and quality of the sound can be increased. and the sound record can he used indefinitely without noticeable deterioration.

Other film roducing liquids may be used in place of t e nitro-cellulose and its solvents, such as acetyl-cellulose in acetic acid. If the acetyl-cellulose is used in its usual Patented N 0V. l1, 1913.

neath is produced on the surface of the cellll@ solvent-chloroform-the solvent will generally attack wax, and therefore the original record should be made of material which is not appreciably dissolved by the solvent of the film material. Water soluble film producing substances can be used, such as silicate of soda, but in thiscase the surface of the record should be capable of being wet evenly, as for instance, by immersing the wax record in weak alcohol and rapidly drying. This destroys the shiny appearance of the surface of the record without hurting the recorditself. Upon immersion in sillicate ofsoda, it will'adhere evenly, and upon drying will give a hard film. This can be made harder by immersion in chlorid of cal cium to form by double decomposition, calcium silicate. The silicate film is not so desirable as the cellulose film, not having toughness to withstand hard usage, although very desirable in view of the cheapness of the material.

The adhesion of the film to the record is very great as it is shrunk under great tension, and notwithstanding long use'of the reproducing ball, it persists in its adhesion to the contour of the sound record.l The thickness of the film may be governed by regulating the strengthl of the solution, a very. dilute solution producing a thin film, as will be understood, and a stronger solution a thicker film. The film must obviously not be thick enough to interfere with the volume of sound produced by the record.

It is evident that for cheapening thefilm, it may be adulterated with various cheaper materials soluble in the solvent and which do not diminish beyond the desirable point.

Attention is hereby directed to the l accompanying drawing forming part of this specification and illustrating diagrammatically the preferred steps of the process described and claimed.

Having now described my invention, what I claim is:

1. The process of imparting a surface hardening to a phonograph record of waxlike material having vertical sound undulations on the outer surface thereof, which consists in immersing the record in a solution of organic material', withdrawing the same from the solution and partially evaporating the solvent therefrom, then again immersing the same in said solution, withdrawing the same, and completely evaporating the solvent therefrom to produce on the record surface thereof a film containing on its outer surface a replica of the record underneath, substantially as set forth.

2. The process of imparting a surface hardening to a phonograph record of waxlike material having vertical sound undulations on the outer surface thereof, which consists in immersing the record in a solution of organic material, withdrawing the same from the solution and partially evaporating the solvent therefrom, then again immersing the same in said solution, withdrawing the same, and rotating the same to completely evaporate the solvent therefrom and to produce on the record surface thereof a ilm containing on its outer surface a replica of the record underneath, substantially as set forth.

This specification signed and witnessed this 10th day of October 1908.

THOS. A. EDISON.

Witnesses:

Danos HOLDEN, FRANK D. Lnwrs. 

